How to print data on client side using Python

Question

I am creating a log watcher to emulate the tail-f functionality in Linux. So, basically here's what I wanna do

1. Write a server code that can detect the changes happening in the log file.
2. If there is a change detected in the log file the server should send the data to the client and the client should print the data.

But here's whats happening

1. The code on the server is able to detect the changes happening in the log file.
2. But the changes are getting printed in the server side only, even though I am sending the server logs to the client
3. Nothing is getting printed on the client side.

Here is my code server.py

import socket
import sys

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((socket.gethostname(), 1243))
s.listen(5)

class Tail():
    def __init__(self,file_name,callback=sys.stdout.write):
        self.file_name = file_name
        self.callback = callback
    def follow(self,n):
        try:
            with open(self.file_name) as f:
                self._file = f
                self.showLastLine(n)
                self._file.seek(0,2)
                while True:
                    line = self._file.readline()
                    if line:
                        self.callback(line)
        except Exception as e:
            print('Failed to open the file. See if the file does not exist or if there is a problem with permissions')
            print(e)
    
    def showLastLine(self, n):
        last_lines = self._file.readlines()[-10:]
        for line in last_lines:
            self.callback(line)

py_tail = Tail('log.log')
while True:
    clientsocket, address = s.accept()
    clientsocket.send(bytes(py_tail.follow(10),"utf-8"))

client.py

import socket
import sys

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((socket.gethostname(), 1243))

while True:
    msg = s.recv(16)
    msg.decode("utf-8")
    print(msg)

for now I have just created a dummy log.log file which looks something like this

1
2
3
4
5

so when I edit the log file and type

6
7
8

and save it the changes are reflected in the output of my server.py file, but I want the output to be displayed on my client.py file, which is not happening.

I am just exploring socket programming, and since I am new to this, this might be silly query that I have but I really need help.

Answer 1

I have changed the code accordingly and this is how I could fix it

server.py

import socket
import time
import sys
import os

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((socket.gethostname(), 1243))
s.listen(5)

def follow(thefile):
    '''generator function that yields new lines in a file
    '''
    # seek the end of the file
    thefile.seek(0, os.SEEK_END)
    
    # start infinite loop
    while True:
        # read last line of file
        line = thefile.readline()
        # sleep if file hasn't been updated
        if not line:
            time.sleep(0.1)
            continue

        yield line

logfile = open("log.log","r")
loglines = follow(logfile)

while True:
    clientsocket, address = s.accept()
    for line in loglines:
        clientsocket.send(bytes(line,"utf-8"))

client.py

import socket
import sys

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((socket.gethostname(), 1243))

while True:
    lines = s.recv(16)
    lines=lines.decode("utf-8")
    print(lines)